Add doc for MidpointRounding

Author: codingseb

README.md

@@ -188,7 +188,7 @@ The evaluation of functions names is case insensitive.
 |**Min**(double nb1, double nb2 ,...)|Return a double value that is the minimum value of all given arguments|`Min(1d, 2.5d, -4d)`|`-4d`|
 |**new**(TypeOrClass, constructorArg1, constructorArg2 ...)|Create an instance of the specified class as first argument and return it. A optional list of additional arguments can be passed as constructor arguments|`new(Random).next(0,10)`|`5d // or a random value between 1 and 9`|
 |**[Pow](https://msdn.microsoft.com/en-us/library/system.math.pow(v=vs.110).aspx)**(double x, double y)|Return a double value that is x elevate to the power y|`Pow(2,4)`|`16d`|
-|**[Round](https://msdn.microsoft.com/en-us/library/system.math.round(v=vs.110).aspx)**(double d, (optional) int digits)|Rounds d to the nearest integer or specified number of decimal places.|`Round(2.432,1)`|`2.4d`|
+|**[Round](https://msdn.microsoft.com/en-us/library/system.math.round(v=vs.110).aspx)**(double d, (optional) int digits, (optional [MidpointRounding](https://msdn.microsoft.com/en-us/library/system.midpointrounding(v=vs.110).aspx) mode))|Rounds d to the nearest integer or specified number of decimal places.|`Round(2.432,1)`|`2.4d`|
 |**[Sign](https://msdn.microsoft.com/en-us/library/system.math.sign(v=vs.110).aspx)**(double d)|Return 1,-1 or 0 indicating the sign of d|`Sign(-12)`|`-1d`|
 |**[Sin](https://msdn.microsoft.com/en-us/library/system.math.sin(v=vs.110).aspx)**(double angle)|Return a double value that is the sine of the specified angle in radian|`Sin(Pi/2)`|`1d`|
 |**[Sinh](https://msdn.microsoft.com/en-us/library/system.math.sinh(v=vs.110).aspx)**(double angle)|Return a double value that is the hyperbolic sine of the specified angle in radian|`Sinh(2d)`|`3.62686040784702d`|